Fuel pump for internal combustion engines



Feb. 15, 1938. o, w, sc ET A 2,108,079

FUELv PUMP FOR INTERNAL COMBUSTION ENGINES Filed Feb. 8, 1936 2 Sheets-Sheet 1 i SIG/0W Oscar MScZaey 6607/36 Z'fiemmeier Feb. 15, 1938.

o. w. SCHEY ET AL. 2,103,079

FUEL PUMP FOR INTERNAL COMBUSTION ENGINES Filed Feb. 8, 1936 2 Sheets-Sheet 2 27 Q g Z5 2 7 IHV 5 l /25%; I A 19 v 2 3 Oscar W 5,2956 y (zeob'yejlfimmier considerable latitude is secured at its edges to the base mem-- Patented Feb. 15, 1938 FUEL PUMP FOR INTERNAL COMB USTION ENGINES Oscar W. Schey Hampton, Va, and George '1'.

Hemmeten-Washington, D. C.

Application February 3', 193s.. s.m.1 No. 63,008

18 Claims. (01. 103-150 V (Granted amend under the m of March a, 1883, as ed April so. 192s; 37.0 o.

of the diaphragm type forinternal combustion engines and moreparticularly to a means for pumping non-lubricant and low viscosity fluids.

as required in solid injection systems for internal combustion engines. 4

An object of the invention is the provision of a simple means for injecting fuel in which there are no rubbing surfaces in contact with the pumped fuel,, eliminating the wearing away of such parts with consequent leakage of fuel or the necessity for frequent replacement of worn parts. Alsoinitial leakage ical clearance is entirely-eliminated Another object of the invention sion of a pumpincorporating means for a positive control and a uniform metering of the discharge occurring in each cycle of" the pumping 1 operation. A further object sion of a means to provide for obtaining a sharp cut-ofl which is essential for eflicient operation of solid injection engines.

With the above and other objects in viw the invention consists in the construction, combination and arrangement of parts as more fully hereinafter. Reference is to be hadv drawings forming a part of this specification in which like reference characters indicate corresponding parts throughout the several views. and in which-- Fig. 1 is a ,sectional view of the preferred embodiment of our invention, U 36 Fig. 2 is a section on the line A--A of Fig. 1,

and

form of the diaphragm actuating mechanism of our invention. A

40: Referring'to the drawings and more particu 'larly to Fig. 1, 29 is a housing secured to a suitable support by fastening elements 35, and has a-base member} rigidly mounted thereon in any suitable manner, we having shown bolts 31 for the purpose. A diaphragm l,

sisting of a thin flexible plate formed to permit of flexure at its central portion, ber.2 by a suitable means 21 in a manner to 50 prevent leakage at this point The diaphragm is thickened somewhat at its circumference and its central portion, the latter being depressed to form a central protuberance 30, there being suflicient clearance between the protuberance and 55 the base member to form. a chamber l The to the accompanying i Fig. 3 his a similar view of a slightly modified ol iuel due to mechanis the proviportion of the diaphragm between the protuberance and the thickened edges is concave to fit over convex member 88 forming a part of the base member 2. The base member is provided with a. suitably. sized passageway 3 to permit adequate, flow into or out of the chamber 4. The entrance to the passageway. is chamiered, as at 23,,to provide a seat for the protuberance of the diaphragm.

Inlet passage I communicates with the main passageway 3 and is provided with a check valve 6 that permits fluid to flow only into the main passageway. Discharge passage 8 alsocommunicates with the main passageway 3 and is likewise provided with a check valve 5 that permits fluid to flow only out of the mainpassageway.

' It will be understood that,

of the invention is the proviwill be'described shaft '22 having a thrust din r 24 permitting.

in a guideway 38' and right angles to itssupport preferably conif desired, springloaded valvesmay be employed in our invention instead of the check valve.

Limiting the volume of chamber 4 to closely 20 approximate the volume of fuel to be pumped per cycle provides uniform metering of the fuel discharged in each cycle of operation. The volume of the chamber is regulated by the permissible movement or outward flexure of the diaphragm; -Such flexure is governed by the position of a wedge-shaped stop 20 which is slidably mounted in the housing and which is provided with a threaded opening to receive a threaded rotary but not axial movement inthe housing...

A suitably calibrated hand wheel 2| provides -easy manipulation of the shaft. The wedgeshaped stop. is mounted inthe. housing to slide to move in aplane at 29, as shown in Fig.2. I

A guide l9, serving as a support for a, sliding cross-head i8, is fixed to the base. Thecrosshead is adapted to abut on the diaphragm and. .the surface 25 01' the stop 20, and it is provided with a concave recess 28 to receive one end ,of a floating link ll. Projections 39 on the crosshead engage in a slot 40 in the wedge-shaped stop 20, more clearly shown in Fig. 2, assuring proper engagement between the cross-head and stop; It will be understood that the abutting l 'fabes of the cross-head and stop are suitably cy le oi operation.

' As a means to control the ejection of fuel we employ a rocker arm l pivoted on a stub shaft ll, One end of the rocker arm carries a roller I! which rides over the surface of a cam 9 mounted on a shaft 34 driven by a suitable element of the engine. The other end of the rocker arm is provided with a threaded transverse bore 26 to receive a threaded adjustable tappet I4 which is adjusted in the bore by a hand wheel"! 5. One end of the tappet is spherically concave to receive an end of the floating link IT. This floating link is the means of inwardly flexing the diaphragm to eject the charge of fuel drawn in by the previous outward flexure of the diaphragm. The link I], owing to its floating characteristic, is free to move with the cross-head when the diaphragm flexes outwardly. By this arrangement a metered amount of fuel is ejected from the pump each time the roller rides over the top of the cam because the link will have the same distance of movement each time due to the locking of the tappet in its adjusted position by the lock lever l8.

For adjusting the pump prior to operation, cam 9 is rotated so that roller I2 is at the extended portion of the cam, which condition representsthe position of the cam for maximum diaphragm deflection. Handwheel I is then rotated so as to deflect the diaphragm until the protuberance 30 seats against chamfered surface 23, after which the tappet is locked by the lever I 6.

With the cam in the position shown in Figure 1, the chamber volume is reduced to its minimum value. As the cam is rotated in the direction indicated by the arrow, spring l3 moves the rocker arm l0 drawing tappet l4 away from the diaphragm. Dueto its own resilience and aided by a primary pressure kept in the intake passage 1, the protuberance 30 of the diaphragm is deflected away from its seat allowing fuel to enter the chamber 4. The motion of the diaphragm away from its seat is stopped when the cross-head comes into contact with the wedge-shape stop 20. The tappet I being moved away from the diaphragm by the action of the rockerarm allows the floating link to be moved by the cross-head. Further rotation of the cam brings the tappet again in the direction of the diaphragm depressing it through the cross-head and forcing the fuel in the chamber 4 out through passageway 3, past check valve 5 into the discharge passage 8. The depression of the'diaphragm continues until the protuberance 30 abuts the chamfered seat 23 thus sealing the passageway 3 against further fuel flow. This is co-incidental with the arrival of the roller l2 at the top of the cam. The action of closing passageway 3 at the end of the pumping stroke is one of the factors accounting for the sharp cut-off which is a feature of the pump. This cycle of operation is repeated for each revolution of the cam.

In Figure 3 we have shown a modified form in which the main passageway is closed by a valve 32 having a spline shaft 33 normally held open by a spring 3|. When the diaphragm is depressed, as previously explained, it abuts the valve, closing it on its seat.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of our invention and that various changes in construction, proportion and arrangement of parts may be made within the scope of the appended claims without sacrificing any of the advantages I factured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What we claim is:

1. In a pump of the class described, in combination, a housing, a diaphragm secured to the housing forming a chamber jointly with the housing, an intake passage and an outlet passage leading to a common port in the housing in communication with the chamber, check valves in the respective passages, an adjustable actuating means for deflecting the diaphragm to close the port, and means for regulating the initial volume of the chamber.

2. In a pump of the class described, in combination, a housing, a diaphragm secured to the housing forming a chamber jointly with the housing, an intake passage and an outlet passage leading to a common port i communication with the chamber, check valves in the respective passages, mechanical actuating means for periodically deflecting said diaphragm in one direction only, and a floating link controlled by said actuating means for regulating the amount of deflection of said diaphragm.

3. In a pump of the class described, in combination, a housing, a diaphragm secured to the housing forming a chamber jointly with the housing, an intake port in the housing in communication with said chamber, a check valve in said intake port, an outlet port in the housing in communication with said chamber, a check valve in said outlet port, a shaft mounted for rotation in the housing, a cam on said shaft, a rocker arm pivotally mounted in the housing, an adjustable lug mounted on said rocker arm and disposed to abut the diaphragm, said rocker arm being, provided with a roller disposed to ride on the periphery of said cam, and resilient means for holding said roller in constant contact with 7 said cam.

4. In a pump of the class described, in combination, a housing, a diaphragm secured to the housing forming a chamber jointly with the housing, a common inlet and outlet port communicating with the chamber, a cross-head withv with the chamber, and means for actuating thelink;

6. In a pump of the class described, in combination, a housing, a diaphragm secured to the housing forming a chamber jointly with the housing, a common inlet and outlet port communicating with the chamber, a tapered member for regulating the initial chamber volume and a floating link for depressing the diaphragm into abutment with said housing in a pumping operation.

'7. In a pump of the class described, in combination, a housing, a diaphragm securedto the housing forming a chamber jointly with the housing, a common inlet and outlet port communicatingwith the chamber, a floating link for deflectingthe diaphragm to its initially deflected position into abutment with the housing, and means for limitingthe return deflection of the diaphragm.

' 8. In a pump of the class described, in combination, a housing, a diaphragm secured to the housing forming a chamber jointly with the housing, a common inlet and outlet port communicatingrwith the chamber, and a floating link for periodically deflecting the diaphragm from the initially deflected position into abutment with the housing, and means for limiting the return deflection of the diaphragm. 1 9. In a pump of the class described, in combination, ahousing, a diaphragm secured to the housing forming a chamber jointly with the housing, a port in the housing in communication with the chamber, a floating link for depressing the diaphragm into abutment with the housing caus: ing the diaphragm to cover said port and meansior actuating the floating link.

10. In a pump of the class described, in com-' a housing, a diaphragm secured to the housing forming a chamber jointly with the bination,

. ing portion abuts with the chamfered seat' covering and closing said port;

12. In a pump-oi the class described, in combination, a housing, adiaphragm-secured to the housing forming a chamber JOLutly with thehous- 45 ing, said diaphragm having a protruding portion, means for regulating the initial clearance between the diaphragm and the housing, a port located in the housing in communication with the chamber and having a chamfered seat at the inlet of the chamber, and means for deflecting the diaphragm until said protruding portion abuts said chamtered seat. 13. In a pump of the class bination, 'a housing, a diaphragm securedto the 55 housing forming a chamber jointly with the hous-v said diaphragm having a protruding porhis;

tion, means for initially deflecting the diaphragm, a port located in the housing in communication with said chamber having a chamIered seat, and means-for deflecting the diaphragm? until said protruding portion abuts said chamfered seat.

14. A pump of the class described comprising a housing, a secured to the housing forming a chamber jointly with the.ho'using, said diaphragm having a protruding portion,

means for regulating the,diaphragm from the initially a housing, a diaphragm secured'to the protruding described, in comthe initial clearance be-. I

tween the diaphragm and the housing, a main port located in the housing in communication with said. chamber, having a ehamfered seat, means for deflecting the diaphragm, pressing said protrudingv portion periodically into'abutment with said chamiered. seat, an intake port in communication with said main port, a check valve 'in said intake port, an outlet port in communication with said main port, and a check valve in said outlet port.

15. A pump of the class described comprising ahousing, a diaphragm secured to the housing forming a. chamber jointly with the housing, said diaphragm having a protruding portion, n'ieans for initially deflecting said diaphragm, a main port located in the housing in communication with the chamber, an intake port in communication with said main port, a check valve in said intake port, an outlet port in communication with said main port, a check valve in said outlet port, and a floating link for periodically deflecting deflected position to a position in which the protruding portion abuts and covers said main port.

16. A pump of the class described comprising a. housing, a diaphragm secured to the housing forming a chamber jointly with the housing, said diaphragmhaving a protruding portion means for initially deflecting the diaphragm, a main port located in the housing in communication with the chamber and having a cha'mfered seat,

an intake port in communication with said main port, a check valve in said intake port, an outlet port in communication with said mairr port, a check-valve in said outlet port, and a floating link ior periodically deflecting the diaphragm from the initially deflected position to a position in which the protruding portion abuts said chainfered seat, thereby closing the main port.

17. A pump or the class described comprising a'housing, a diaphragm secured to the housing forminga' chamber jointly with the housing, a common port in the housing in communication with said chamber, an intake port in communication with said common port, a check valve in said intake port, an outlet port in communication with said common port, a check valve in said outlet port, and'a floating link for periodically deflecting said diaphragm into abutment with the'housing causing the diaphragm to cover and seal said common port.

18.*In a pump of the class described, in combihation, a housing, a diaphragm secured to the housing forming a chamber jointly with the housing, means for initially deflecting the. diaphragm. a port located in the housing in com- Jmunication with the chamber, the port being provided with a valve havinga resilient means for keepingsaid' valve normally unseated, and -means for periodically depressing the diaphragm with the valve causingsaid valve to seat and close said port. OSCAR W. SCHEY.

, GEORGE '1. HEMMEI'ER.

' 4mm its initially deflected position into abutment v 

